CVE-2021-3631

Publication date 2 March 2022

Last updated 18 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels. This flaw allows one exploited guest to access files labeled for another guest, resulting in the breaking out of sVirt confinement. The highest threat from this vulnerability is to confidentiality and integrity.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libvirt	26.04 LTS resolute	Fixed 7.6.0-0ubuntu3
	25.10 questing	Fixed 7.6.0-0ubuntu3
	25.04 plucky	Fixed 7.6.0-0ubuntu3
	24.10 oracular	Fixed 7.6.0-0ubuntu3
	24.04 LTS noble	Fixed 7.6.0-0ubuntu3
	23.10 mantic	Fixed 7.6.0-0ubuntu3
	23.04 lunar	Fixed 7.6.0-0ubuntu3
	22.10 kinetic	Fixed 7.6.0-0ubuntu3
	22.04 LTS jammy	Fixed 7.6.0-0ubuntu3
	21.10 impish	Not affected
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 6.0.0-0ubuntu8.16
	18.04 LTS bionic	Fixed 4.0.0-1ubuntu8.21
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libvirt	Upstream: 1507350

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.3 · Medium

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	None

Scores

Parameter	Value
Base score	6.3 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

References

Related Ubuntu Security Notices (USN)

USN-5399-1
libvirt vulnerabilities
2 May 2022

Other references

https://www.cve.org/CVERecord?id=CVE-2021-3631